Process for treating liquids



Patented July is, 1940 PATENT OFF PROCESS FOR TREATING LIQUIDS Oliver M. Urbain, Columbus, Ohio, assignor to Charles H. Lewis, Hamster, Ohio ,No Drawing. Amflioation May 10, 1938,

7, Serial No. 207,164 W V 19 Claims. (Cl. 210-24) This invention relates to a process for liquid treatment.- More particularly, it relates to the removal of undesirable anions such as sulfate, phosphate and fluoride ions from liquids by con.-

tacting the liquid containing such undesired ions? with a particular anion exchange medium. This invention also relates to the recovery of valuable acids from liquids by an anion exchange process.

Specifically, the invention contemplates the eilecting of anion exchange by the use of alkali treated asphaltic material. The materials employed are preferably prepared at temperatures below those efiective to cause decomposition of the asphaltic materials.

Liquids containing certain anions such as sulfates are unsatisfactory for many uses because of their permanent hardness, and the removal of these undesirable anions presents a dimcult problem. The present invention provides an exceedingly simple and inexpensive process for effecting the removal of such anions. The process will additionally remove other undesirable anions 'from the liquid being treated. For example, it has recently been found that potable waters in a number of communities contain fluoride anions in quantity sufficient to be detrimental to the health of consumers of such waters. By treatment of such waters with the materials prepared in accordance with the hereinafter disclosed process, the fluoride content can be reduced below the toxic point. The process of the present invention is further especially applicable to the recovery of acids in a highly efficient manner from solutions containing the same.

The invention here disclosed resides in the discovery that certain bituminous substances which I term asphaltic materials, when treated with concentrated solutions of alkalies such as sodium or potassium hydroxide, at temperatures substantially below the fusing point of such materials, yield water insoluble anion exchange materials capable of effecting efiicient anion exchange when contacted with liquids containing undesirable anions or acids which it is desired to remove or recover.

By the term "asphaltic materials is meant those bituminous substances termed asphalts, asphaltites, and asphaltic pyrobitumens. The term asphalts includes a species of bitumens and also certain pyrogenous substances, of dark color, variable hardness, comparatively non-volatile; composed principally of hydrocarbons, substantially free from oxygenated bodies; containing relatively little to no crystallizable paraffin; sometimes associated with mineral matter, the nonmineral constituents being fusible, and largely soluble in carbon disulflde yielding water insoluble sulfonation products.

The term asphaltites" includes that species of bitumens having similar properties to the asphalts except that the non-mineral constituents are difiicultly fusible.

The term asphaltic pyrobitumens refers to those substances which, when subjected to heat or fire, will generate or become transformed into bodies resembling bitumens, and which are dark colored, comparatively hard and non-volatile solids; composed of hydrocarbons, substantially free from oxygenated bodies; sometimes associated with mineral matter, the non-mineral constituents being infusible and largely insoluble in carbon disulfide.

It will thus be seen that the common characteristics of the class of bituminous substances which are termed "asphaltic materials are their semi-solid to solid consistency and their substantial freedom from contained oxygenated bodies. Included among the materials embraced by this term are the native asphalts such as those occurring naturally in a pure or fairly pure state and those associated naturally with a substantial proportion of mineral matter, the pyrogenous asphalts such as residues, obtained from distillation, blowing, etc., of petroleum and the pyrogenous treatment of wurtzilite; the asphalties, such as gilsonite, glance pitch, and grahamite; and the asphaltic pyrobitumens such as elaterite, wurtzilite, albertite, impsonite, and the asphaltic pyrobituminous shales. All of these materials, when treated with concentrated solutions of alkalies in accordance with the procedure to be described hereinbelow, yield materials which are effective for the treatment of liquids in accordance with my rocess. Such alkali treated materials are embraced by the hereinafter employed term alkali treated asphaltic materials."

In the preparation of these new liquid purification reagents, asphaltic materials as hereinabove defined are treated with concentrated solutions of alkalis. The asphaltic materials are first granulated to produce a relatively fine powder which will range from approximately 10 to 50 mesh. The powdered asphaltic materials are then slowly added to a concentrated solution of sodium hydroxide or potassium hydroxide with constant stirring. After introduction of such materials to the alkali solution, the mass is slowly heated to a temperature of about 100 C., while being constantly agitated. The temperature prevailing in this step should not exceed, 105 C. The reaction will be completed in about one hour. During the heating period, a curd is formed. After the reactions are completed, the curd which has been formed is removed and the excess alkali may again be used in the further treatment of additional asphaltic materials. The quantity of the alkali employed should, of course, at all times be substantially in excess of the total demand of the asphaltic materials.

After removal of the curd, it is thoroughly washed with water and broken up into small pieces, when it should be additionally washed until substantially free of alkali. The material, after being thus washed free of alkali, is dried at a temperature of around 105 C. and is then ready for use in liquid treatment processes. The speciflc strength of the alkali employed is not of much consequence except, of course, that the solution should be thoroughly concentrated.

The finished product produced in accordance withtheabove outlined procedure is about 25% greater in weight than the asphaltic material employed in its preparation and is about 100% greater in volume than the original asphaltic material. The physical properties of the finished product render it especially well adapted for use in water treatment.

It is of the utmost importance that the asphaltic materials not be subjected to heat suflicient to cause the same to undergo a change in composition. When an asphaltic material is heated to temperatures of the order of its fusing point, it undergoes a change in composition and is no longer particularly well adapted for use in my process. I regard the avoidance of the employ ment of excessive heat as a critical factor since I have found that where an alkali treatment of asphaltic materials is effected at temperatures of the order of their fusing point, the resultant material is much less efficient than is the alkali treated asphaltic material prepared in accordance with my hereinbefore described method. It thus appears that the naturally occurring volatile constituents in the asphaltic materials are responsible for the efiicient liquid purification properties of such materials, when alkali treated, and care should be taken to retain these constituents' I base this belief upon the fact that I have found the native asphalts, the native asphaltites, and the naturally occurring asphaltic pyrobitumens to be somewhat superior to the pyrogenous asphalts, obtained by heat treatment of petroleum and pyrobitumens. It is believed that the application of heat causes a loss in the volatile constituents and a corresponding increase in the fixed carbon. I have found that the efficiency oil my reagents, in removing anions or acids from liquids, is in inverse ratio to the fixed carbon contents thereof. Accordingly, it is one, of the purposes of my invention to avoid excessive heat treatment of the asphaltic materials employed in order to maintain a low fixed carbon content therein.

Accordingly, the expression"alkali treated asphaltic materials as hereinafter employed, is intended to designate such materials prepared at temperatures well below those which will effect a change in the composition of the bituminous substance.

In. the applicationof the process to the treatment of liquids, either of two methods may be employed: (1) the liquid to be treated may be passed through a filter charged with alkali treated asphaltic material; or, (2) the powdered alkali treated asphaltic material may be added to the liquid with agitation in advance of a conventional coagulation step.

The choice between these methods will depend upon the nature of the liquid being treated and whether it is desired to recover the anions being extracted by exchange from the liquid being treated. r

The following illustrative examples indicate the adaptation of alkali treated asphaltic materials in processes for the removal or the recovery of anions from liquids.

Example 1 An Egyptian variety of natural asphalt was alkali treated in accordance with the foregoing procedure. The granular material, after drying at a temperature of about C., was added to a water containing 500.0 parts per million of permanent hardness determined as sulfate. Approximately 9 pounds of the alkali treated asphaltic material was added perthousand gallons of water and the mixture was agitated for a period of approximately 20 minutes. The water was then filtered to remove the reagent and the filtrate tested for its sulfate content by the barium chloride method. This operation efiected 'a reduction in the sulfate content of the liquid pacity of the alkali treated asphaltic material.

Example 2 An alkali treated asphaltite, prepared by the reaction of .a natural occurring gilsonite (such as that found in Utah) with concentrated sodium hydroxide in accordance with the procedure above described, was placed in a conventional water softening filter. Through this filter was then passed a raw water, similar to that treated in Example 1, containing 500.0 parts per million of permanent hardness determine as sulfate. The permanent hardness content of this water atter treated with the alkali treated gilsonite, :was found to be approximately 55.5 parts per million.

Examples 1 and 2 show that an alkali treated asphaltic material possesses an extremely high capacity for the removal of permanent hardness from water.

- Example 3 A residual asphalt produced by the steam distillation of an asphaltic petroleum, was alkali treated by the procedure hereinbefore described and was then added in granular form to a liquid :containing 500.0 parts per million of permanent Example 4 A rock asphalt, i. e., a native asphalt associated with mineral matter such as sand, sandstone, limestone, etc., which had been refined by a distillation process, was alkali treated in accordance with theforegoing procedure. After drying at 105 0., the granular alkali treated refined asphalt was added to a liquid containing 500.0

parts per million of permanent hardness. After agitation and filtration, the filtrate was tested and found to contain approximately 132.4 parts per million of permanent hardness determined as sulfate.

The results of Examples 1 to 4 indicate that ed. However,

because of the availability of the latter as by-products from a number of commercial operations,

it is believed that their utilization, when alkali treated, as anion exchange materials, is commercially practicable.

, Example 5 Alkali treated gllsonite as used in Example 2,

above, was placed ing apparatus and a in a conventional water softenliquid containing 250.0 parts per million of phosphate was passed through this The efiluent from this treatment was tested for phosphate content and it was found that 75% of the anions had been removed by contact with the alkali treated gilsonite cordance with the foregoing procedure.

the phosphate content of the liquid maonly was prepared in ac- Not terially lowered, but the removed phosphate ions were available generation of described below.

for recovery by a process of rethe exchange medium, as will be Example 6 A commercial water supply, which had been found to contain approximately 7.0 parts per million of fluoride ions,

was treated with granular alkali treated natural asphalt, as used in Example 1 above, by the addition of the asphaltic material to the fluoride containing liquid. Ap-

proximately 10 pounds of the alkali treated nat-- ural asphaltum was added per thousand gallons of water and riod of approximately 20 minutes.

the mixture was agitated for a The fluoride content of the filtrate, after removal of the reagent by filtration,

ions had been per million. Such the treated liquid point. of 1.0 part such liquid, by

indicated that the fluoride reduced to approximately 0.8 part a content of fluoride ions in is below the recognized toxic per million and accordingly this treatment had been made available for use as potable waters without the harmful effects which would have resulted from its use prior to the reduction in its fluoride content.

Methods for asphaltic mate the process of treatment of the tions of anion hydroxide and ed exchange material displays substantially the same capacity initially prepared reagent. regeneration liquid depends the anion desired in exchange as does the The choice of the upon the nature of the exchange position in for anion the reagent; the use of a 5% solution of sodium hydroxide places hydroxyl ions in the exchange medium, whereas the use of a sodium chloride solution for regeneration places chloride ions in the exchange position in When the process of acids from the reagent. is employed for the recovery liquids, the acid containing liquid is first fully passed through the filter charged with an alkali the exchanger treated asphaltic material. When becomes exhausted, it can be regenerated in the manner above indicated. The

acid is then recovered by acidifying the wash water employed in the regeneration of the exchange medium or by other conventional methods. Recovery is thus made possible because of the much higher concentration of the acids in the effluent of the regeneration treatment than the acid concentration in the original liquid.

For example, if the alkali treated asphaltic material had-\initially been employed to remove valuable anions such as phosphates, as shown in Example 5 above, the effluent from the regeneration wash will be found to be rich in phosphate ions. These may be recovered from the eiiluent obtained by the regeneration process, by acidification or other well known methods.

The foregoing description and examples which I have given are illustrative only and it is to be expressly understood that they are not to be considered as limiting this invention beyond the scope of the sub-joined claims.

Having thus descr'bed my invention, what I claim is:-

l. A process for treatment of liquids which comprises contacting said liquids with an alkali treated asphaltic material.

2. A process for the treatment of liquids comprising passing said liquids through a fllter charged with an alkali treated asphaltic material.

3. A process for the treatment of liquids comprising adding an alkali treated asphaltic material to said liquids and thereafter removing said asphaltic material from said liquids.

4. A process for the treatment of liquids which comprises contacting said liquids with an asphaltic material which has been alkali treated at temperatures below that at which said asphaltic material loses its volatile constituents.

5. A process for the treatment of liquids which comprises contacting said liquids with an alkali treated asphaltic material, said asphaltic material characterized by its semi-solid to solid consistency and its substantial freedom from oxygenated bodies.

6. A process for the treatment of liquids which comprises contacting said liquids with an as phaltic material which has'been alkali treated at a temperature below that at which said asphaltic material loses its volatile constituents, said bituminous substance characterized by its semi-solid to solid consistency and its substantial freedom from oxygenated bodies.

7. A process for the treatment of liquids which comprises contacting said liquids with an alkali treated asphalt.

8. A process for the treatment of liquids which comprises contacting said liquids with an alkali treated pyrogenous asphalt.

9. A process for the treatment of liquids which comprises contacting said liquids with an alkali treated natural asphalt.

10. A process for the treatment of liquids which comprises contacting said liquids with an alkali treated asphaltite.

11. A process for the treatment of liquids which comprises contacting said liquids with an alkali treated asphaltic pyrobltumen.

12. A process for effecting anion exchange in liquids which comprises contacting said liquids with an alkali treated asphaltic material. V 13. A process for the removal of undesired anions from liquids which comprises contacting said liquids with an alkali treated asphaltlc material.

14. A process for reducing permanent hardness in liquids which comprises contacting said liquids with an alkali treated asphaltic material.

15. A process for the removal of sulfates from liquids which comprises contacting said liquids with an alkali treated asphaltic material.

16. A process for the removal of fluorides from liquids which comprises contactingwaid liquids with an alkali treated asphaltic material.

17. A process for recovering acids from aqueous solution comprising effecting exchange of the anions of the acids with the anions or an alkali treated asphaltic material and recovering the anions from the asphaltlc material.

18. A process for exchanging anions from aqueous solutions and effecting regeneration-of the anion exchange medium, comprising first efi'ect- 

